If this is correct it may be that the different White olm populations represent different species which resemble one another by convergent evolution, and which have partly or mostly fused as they have met up within the Dinaric karst system.

Having said that, one of the most interesting contentions made recently about olms (Sket 1997) is that the different cave-dwelling olm populations may have evolved independently from different ancestral populations.

What might be the most fascinating fact concerning olms is the most poorly-known and least mentioned one: the 1986 discovery of a surface-dwelling olm, described in 1994 by Boris Sket and Jan Willem Arntzen.

In Slovenia this little beast is famous, because it lives in that country's famous caves, notably Postojna. Slovenes like to call it the "human fish" (človeška ribica) because its color reminds them of Caucasian human skin.